Diffraction effect of the injected beam in axisymmetrical structural CO2 laser

Diffraction effect of the injected beam in axisymmetrical structural CO2 laser is studied based on the injection-locking principle. The light intensity of the injected beam at the plane where the holophotes lie is derived according to the Huygens–Fresnel diffraction integral equation. And then the main parameters which influence the diffraction light intensity are given. The calculated results indicate that the first-order diffraction signal will play an important role in the phase-locking when the zero-order diffraction cannot reach the folded cavities. The numerical examples are given to confirm the correctness of the results, and the comparisons between the theoretical and the experimental results are illustrated.

► Diffraction effect of the injected beam is studied based on Huygens–Fresnel theory.
► Main parameters which influence the diffraction light intensity are given.
► The first-order diffraction signal will play an important role in the phase-locking.